1. Field of the Invention
The present invention relates to a control device, and more particularly, to an apparatus and method for communicating between a host computer system and at least one target system with a remote control system.
2. Art Background
A mouse, or a cursor control device, is an instrument that is used to translate the motion of a user's hand into a series of electrical control signals indicative of that hand movement. The mouse is coupled to a computer where the mouse generated control signals are used to position a cursor on a computer display. An optical mouse is a cursor control device that uses optical sensing to generate the electrical control signals. An advantage of the optical mouse over a traditional mechanical mouse is that the optical mouse does not employ any moving parts to generate the control signals. The optical mouse emanates an optical signal, usually in the infrared range, generated from a light emitting diode (LED). To generate the control signals, the mouse is moved on a reflective pad having a large number of equally spaced vertical and horizontal lines. The vertical and horizontal lines have a different color than the background of the reflective pad. The optical mouse is placed on the reflective pad such that the optical light from the LED is reflected from the pad back into the optical mouse.
The optical mouse further includes input optics and optical sensors mounted on the bottom of the mouse. The optical sensors generate an electrical signal proportional to the light incident upon the optical sensor. The LED and the optical sensors are arranged such that the light emanating from the LED is reflected off the pad and onto the optical sensors. To operate the mouse, a user moves the optical mouse across the reflective pad such that the optical light crosses over the horizontal and vertical lines. The amount of light reflected is decreased when the light crosses over one of the horizontal or vertical lines on the pad. Consequently, the light incident upon the photo diodes is decreased, and the mouse is able to detect the crossing of the line. The optical mouse generates four quadrature signals to indicate the movement to the computer based on the mouse crossing the horizontal and vertical lines. Typically, these four parallel quadrature signals are coupled to a standard serial interface such as a universal asynchronous receiver transmitter (UART). The UART converts the quadrature signals into an encoded stream of serial data for transmission to the host computer system.
Applications in optical transmissions are also found in consumer electronic devices. Consumer electronics devices, such as televisions and video cassette recorders (VCRs), often include remote control systems. Manual control systems, unlike remote control systems, require the user of the electronic device to physically go to the device to manipulate knobs and buttons. With the use of remote control, the user can control the device, from a limited distance, with a remote control unit thereby eliminating the need to physically touch the controls and adjustments on the device itself. The basic remote control system contains a transmitter on the remote control unit and a receiver on the device. The remote control unit contains buttons where each button correlates to a device function. Each function is represented by an unique function code having a string of logical ones and zeros. When the user presses a button on the remote control unit for a desired function, the remote control unit retrieves the corresponding function code and transmits it to the device. Various manufacturers of remote control systems use both different function codes and encoding techniques to modulate the function codes. The device receives the modulated function code, demodulates the code back into a string of ones and zeros, and performs the desired function.
Multi-media is the integration of several audio and video production units into a single controllable unit. Multi-media projects cover many communication media types, including printed materials, audio programs, television shows, feature films and many others. The ability to integrate the functions of the resources utilized in the production of multi-media projects into a single shared system provides a level of performance and capability unknown in the prior art. A computer workstation may be the center of such a system by providing memory and digital processing capabilities. Referring to FIG. 1, a multi-media system is illustrated. A central control computer 20 is networked to: television 22; video cassette recorder (VCR) 24; video laser disc 26; and compact audio disc 26. With such an integrated system, the user, at central control computer 20, can transfer information among the devices attached to the integrated network.
A multi-media system, such as the one illustrated in FIG. 1, provides the user with a very powerful audio visual production center. For example, the user may wish to manipulate a video image stored on laser disc 26. First, the video image must be transferred over the network from laser disc 26 and stored in memory in central control computer 20. To accomplish this task, the user would command, by a remote control unit, laser disc 26 to play the video image over the network. After the video image is transferred to central control computer 20, the user may add special effects to the video image creating these effects directly on the computer. After generating the enhanced video image, the user may wish to store the video image on VCR 24. To accomplish this task, central control computer 20 sends the video image via some kind of interconnect (often in analog video), and the user remotely controls VCR 24 to record the enhanced video image. In this example, in order to control both laser disc 26 and VCR 24, the user is required to use two remote control devices. Furthermore, the user is required to use a computer interactive device such as a mouse.